1. Field of the Invention
This invention relates to a fuel cell, e.g., a hydrogen-oxygen type fuel cell, comprising (1) a generator cell having a fuel gas chamber, an oxidizing gas chamber and an electrolyzing solution chamber and (2) fuel gas and oxidizing gas circulating circuits for supplying the fuel gas and the oxidizing gas to the fuel gas chamber and to the oxidizing gas of said generator cell.
2. Prior Art
One of the problems as to the fuel cell is to provide a system capable of removing the formed water from the generator cell during the generating operation and discharging the removed water out of the fuel cell. It is the usual practice to remove the formed water from the interior of the generator cell by taking out the formed water in the form of steam using the carrier gas from the gas chamber side of each electrode face.
Another problem is a necessity to keep constant the concentration of the electrolytic solution irrespective of the change of the operating conditions, as the concentration of the electrolytic solution greatly influences the properties of the fuel cell. On the other hand, a porous gas diffusing electrode is used in the fuel cell, and it is necessary in order to operate the fuel cell stably for long period of time to keep the gas chamber side of the electrode always in the dried state. Accordingly, larger amounts of water than the formed water must be removed during the generating operation, but this results in the reduction of the amount of electrolytic solution, i.e. the increase of the concentration thereof. To solve this problem, such amounts of water as deducting that of water formed during the generating operation from that of water separated from the fuel cell by above described process, i.e., excess amounts of water deducted from the electrolytic solution, must be returned to the electrolytic solution, or clean water must be replenished to the electrolytic solution to keep constant the concentration thereof.
A further problem of the fuel cell is the necessity of balancing the pressure of hydrogen or oxygen gas with that of the electrolytic solution thereby to prevent the blowing of the gas into the electrolyzing solution chamber or inversely to prevent the penetration of the electrolytic solution into the gas chamber, for the purpose of keeping a three phase zone. If the pressure ballance between the gas and the solution is destroyed, each gas blows through the gas chamber into the electrolyzing solution chamber, or the electrolytic solution penetrates through the electrolyzing solution chamber into the gas chamber, thus making it impossible to maintain the three phase zone.
A still further problem of the fuel is the necessity to keep constant the operation temperature of the fuel cell by removing the internal heat generation which is caused by the voltage drop due to the polarization potential of each electrode and the resistance of the electrolytic solution. One of the conventional temperature controlling methods is to flow intermittently cooling water by the operation of an electromagnetic valve. This method, however, is not favorable, since the amplitude of the temperature change becomes remarkable, and, moreover, the electromagnetic valve must be operated frequently to decrease the amplitude of the temperature change, thus shortening the life of the electromagnetic valve. Another method is to use a proportional valve such as is used in the ordinary plant, but proportional valves are not suitable as to shape, size and weight. Furthermore, both methods require electric operation, which consumes the electric power to reduce the total generating efficiency and requires a temperature detector, a relay, and an electric amplifier. Many of such electric instruments make intricate the structure of the fuel cell generating apparatus.